The Romania-born population increased by 80,000 to 390,000, and resident Romanian nationals rose by 83,000 to 411,000, the estimates say, a leap of 25% on the previous year.

Romanians are now more numerous in the UK than Irish nationals and Indians. However, they still lag behind people from Poland.

“Poland-born residents and Polish nationals were the most common populations from outside the UK, with an estimated one million Polish nationals now living in the UK. However, the largest increases in population were seen from those born in Romania and those with Romanian nationality,” said Nicola White of the Migration Statistics Division at the ONS.

Romania joined the European Union in 2007 but its nationals have only been able to live and work freely in the UK since 2014.

A separate report by the ONS in February this year found that the number of people moving to the UK from the European Union had dropped to its lowest for over four years.

The number of EU citizens leaving the UK to return to their home countries rose to its highest level for nearly a decade last year.

The latest figures show that 3.8 million (61%) of 6.2 million non-British nationals living in the UK in 2017 were EU nationals, a rise of 1% on 2016.

Under an agreement struck between the EU and the UK in the Brexit negotiations, people from the EU who move to the UK by the end of 2020 will be able to apply for “settled status” allowing them to stay permanently, once they have been resident for five years.